Editing Neutron reflector (section)

{{Short description|Material with the ability to reflect neutrons; used to control fission reactions}}
{{For|imaging techniques using specular reflection of neutrons|Neutron reflectometry}}
{{more sources needed|date=February 2024}}

[[File:Neutron reflector RK01.svg |thumb |Thermal neutron flux in an unreflected and a reflected nuclear reactor]]

A '''neutron reflector''' is any [[material]] that [[Reflection (physics)|reflects]] [[neutron]]s. This refers to [[elastic scattering]] rather than to a [[specular reflection]]. The material may be [[graphite]], [[beryllium]], [[steel]], [[tungsten carbide]], [[gold]], or other materials.  A neutron reflector can make an otherwise [[subcritical]] mass of [[fissile material]] critical, or increase the amount of [[nuclear fission]] that a [[critical mass|critical or supercritical mass]] will undergo.<ref>{{cite web |title=Neutron Reflector |url=https://www.nuclear-power.com/nuclear-power-plant/nuclear-reactor/neutron-reflector/ |website=Nuclear Power}}</ref>{{better source needed|date=February 2024}} Such an effect was exhibited twice in accidents involving the [[Demon core|Demon Core]], a subcritical [[plutonium]] [[Pit (nuclear weapon)|pit]] that [[Criticality accident|went critical]] in two separate fatal incidents when the pit's surface was momentarily surrounded by too much neutron reflective material.